Labview Based Remote Controlled Automatic & Manual Bell For Boarding and Day Schools

Transcription

1 The International Journal Of Engineering And Science (IJES) Volume 2 Issue 7 Pages ISSN(e): ISSN(p): Labview Based Remote Controlled Automatic & Manual Bell For Boarding and Day Schools Joseph Habiyaremye Department of Electronics and Instrumentation, Bharathiar University ABSTRACT A LabVIEW based automatic or manual school bell is a project which shall help head- teachers to remotely control the ringing of a bell either automatically or manually in their schools.in this system, all bell timings and durations are predefined and depend on: School type (day or boarding)or School organization. These different timings are defined in LabVIEW s block diagram part. The front panel will be user interface, from the user interface: i. The user(head-teacher) will start by entering the current time, from his/her watch for initialization purpose ; ii. The user can manually switch ON the bell, for example in case of urgent meeting; iii. The user can know the current teaching hour, the current teaching period; iv. The user can know if the bell is ringing or not; as the bell is remotely controlled At the end or starting of each time slot, LabVIEW will generate a signal through Arduino microcontroller which is interfaced to a Zigbee transceiver and this Zigbee will transmit this information to a second remote Zigbee which is interfaced to an AC bell through a MOSFET and Relay. The time duration for the bell to ring is defined in LabVIEW itself. The connection of Arduino to LabVIEW requires a plug in called LIFA (LabVIEW interface for Arduino).The Zigbee transceiver are configured by help of X-CTU,TMFT or any other Terminal software by using AT commands (Zigbee series 2 are used).the Zigbee modules are configured in IO scheme; network scheme also can be used if some other controls are added to the system. This project, an installer can be done for easy distribution. This project can even be used in colleges and universities as well as in some companies KEYWORDS: Arduino Uno, AT commands, LabVIEW, LIFA, ZigBee Network Date of Submission: 16 July 2013 Date of Publication: 7, July I. INTRODUCTION All over the world, high schools use timetable for subjects, classrooms, teachers and time slots allocation so that they can have an organized education. In a timetable each subject is assigned a given time slot which may change according to given school. In timetable teachers are assigned different subject in different classrooms, one teacher may teach one or more than one subject in different classrooms, just in different time. A typical timetable has: all school teachers names, all subjects names, teaching time, break time, lunch time and it shows also the starting and the ending time for a period of one week and it is in form of table. In each and every school, there is either electrical or mechanical bell which is used to give signal for each beginning and end of each time slot and this bell is manually controlled and there must be someone called timekeeper who have to ring that bell. Sometimes, the timekeeper forgets to ring that bell which will totally disturb the teaching structure. This project comes as solution to this problem in form of LabVIEW based remote controlled automatic & manual bell for boarding and day schools II. OBJECTIVE & APPROACH To develop a LabVIEW [1] based remote controlled automatic & manual bell for day and boarding schools to be used in education field for timetable monitoring purpose, this system may also be used in some companies where the time slots distribution is required. III. SYSTEM DESIGN The IJES Page 96

2 3.1 case study This system has been designed and implemented according to ADB (Association des Anciens de DON BOSCO)[2] Nyarutarama one high school from Rwanda. In this day school: There are around 50m from head teacher s office to the location of the bell; Classes start at 07h00 am and end at 02h10 pm; Each time slot is 50mins wide; The break time is equal to 30mins, this time is even used for students to take some snacks; After 02h10 pm classes and offices are closed; this is an off class time; A day is divided into two periods, first period and second period; The time slots allocation is shown in table below: Table 1: ADB Nyarutarama Teaching time slots allocation Design of the transmitting end part The transmitting end part is composed by an HMI (Human Machine Interface), a PC with LabVIEW installed with LabVIEW interface for Arduino (LIFA) [3] it has also an Arduino [4] microcontroller a transmitting Zigbee[5]. Figure 1: Transmitting end block diagram HMI This is the main part of the system, it is nothing but a PC with LabVIEW program installed and that LabVIEW program has LIFA as a plug -in so that the Arduino microcontroller can be accessed from LabVIEW System user interface As we can see on the figure below, from the user interface, the user: The IJES Page 97

3 Figure 2: System user interface Starts by imputing the current time, taken from his/her watch Can know if the bell is ringing or not; Can start or stop this application; Can manually control the bell; Can know the current teaching period LabVIEW Block diagram As LabVIEW is a graphical programming language, its coding is in form of block diagrams as it is shown below: Figure 3: LabVIEW block diagram In LabVIEW programming side, all time slots are defined and some formulae are used for different conversion and comparisions, all those blocks are placed inside a while loop as the system runs continously Arduino Uno Microcontroller The IJES Page 98

4 Arduino is a microcontroller board based on ATmega 328. It has 14 digital input/output pins (of which 6 of them can be used as PWM output) 6 analog inputs, a 16 MHz crystal oscillator, USB connection, a power jack, an ICSP header and reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with an AC to DC adapter or battery to get started LIFA LabVIEW Interface For Arduino is a kind of plug in which must be installed in LabVIEW so that it can recognize and work together with Arduino Microcontroller. For LabVIEW to work together with Arduino, a software called VI package[6] Manager is required which is the recommended method for downloading and managing the LabVIEW add-ons and give an instant access to the add-ons on the LabVIEW tool network, this VI package Manager works with LabVIEW 2009 and later. The following steps are used: From VI package Manager browse LabVIEW interface for Arduino; Install LabVIEW interface for Arduino; Connect your Arduino to your computer; Open Arduino IDE; User this path(for LabVIEW2011 installed on driver C) : C:\Program Files\National Instruments\LabVIEW 2011\vi.lib\LabVIEW Interface for Arduino\Firmware\LIFA_Base; Open LIFA_Base file and upload it to your Arduino ; Close the Arduino IDE Transmitting Zigbee Zigbee is wireless communication protocol which is working on IEEE standard. In this system, Trang [7] module has been used Zigbee configuration Zigbee module configuration or reading is achieved by using a terminal application such as HyperTerminal; in this system TMFT 2.6 software has been used Command mode Command mode is used for reading or modifying the parameter of a module. Once the command mode is initiated, incoming character through serial port are considered as commands Entering AT Command Mode The AT command mode is entered by taping +++ symbols within a short time which can be estimated to one second, the following is the AT command format: Figure 4: AT command format The given example would change the Zigbee module channel to 0X0F (15). To store that value to memory, we have to send write command else the value will be lost once the module is re-booted. When the command is sent to module, the module will execute the command and if the execution is successful the module return an OK message otherwise an error will be shown. To exit the AT command mode, send ATGEX command Zigbee module programming The IJES Page 99

5 Series 2 Zigbee modules can be used in Unicast network, Broadcast network or Peer to Peer (point to point) network. In this system, they have been used as in Unicast network as shown below: Figure 5: Zigbee Pee-to-peer communication In any networking scheme, address is given to each and every network device. Let Zigbee 1 be source and Zigbee 2 be destination. Then addresses are given as shown: Table 2: Zigbee addressing mode Programming of each module follows these steps:[7] 1 :Open window HyperTerminal (TMFT 2.6) ; 2 :Connect the Zigbee module to the serial/usb port; 3 :Choose the appropriate port and serial parameters in terminal software(tmft2.6); 4 :Configure the module using AT command By using the above steps, transmitting and receiving Zigbee are configured as follow: These two Zigbee must have the same settings i.e. baud rate, channel, data bit, etc. One Zigbee should be configured with I/O pins as input and other with I/O pins as an output. For setting I/O pins as input and output the following steps are followed: o Enter the command mode with +++ o Enable the desired I/O pin as input with command ATIDXX where XX indicate which pin to be enabled. In this system first I/O line ID0 is used. For configuring it to digital I/O input, the ATID02 is used, and wait for OK response. o Write the parameter to the memory with ATGWR command. o Exit command mode with ATGEX command. o Follow the same steps for configuring the receiving Zigbee o After receiving the OK response from module, write it to its memory and exit the command mode Receiving end side The receiving end part is composed by a receiving Zigbee interfaced to an electrical bell, the interfacing circuit is nothing but a MOSFET and relay as is shown below: Figure 6: receiving end Block Diagram As you see from the above circuit, the receiving end side has two different power supplies one Ac and other DC. The DC power supply supplies Zigbee through a zigbee shielder as Zigbee must be supplied by 3.3V Schematic diagram for receiving end side The receiving end ciruit is detailled below: The IJES Page 100

6 Figure 7: The receiving circuitry showing the state of the bell when there is no signal received by Zigbee The above circuit is a 12V DC regulated power supply along with an electrical bell and its interfacing circuit. For simultaion purpose, a swich has been used as an output from receiving zigbee, as it is shown when the switch is open (when no signal availble at the output of zigbee) the relay is open and the bell is in OFF condition. Figure 8: The receiving circuitry showing the state of the bell when a signal is received by Zigbee From the above circuit, we can see that when the switch is closed (the output of zigbee Pin is high) the relay closes and the bell rings.(fernandez-lopez, Afonso et al. 2012) 3.2 System working principale The user (headtecher) will start by entering the current time from his/her watch for unitialization purpose, LabVIEW program will compare the entered time and the computer s time and if there is a differnce of two minutes, it will ask the user the match both times (computer s time and watch s time). If both times are matched, LabVIEW program will start comparing the current time to predifined time slots. If the current time is equal to the end or the starting of any time slot, LabVIEW will generate a signal which will be transmitted to transmitting zigbee through arduino and arduino shielder. The same event will happen also if the user manually press the control button, for example in case of urgent meeting. The imformation from the transmitting end will transmitted to the receiving end through wireless communication. Reaching the receiving Zigbee, one of its I/O pin configured as output pin will be high and as is connected to the gate of MOSFET, the MOSFET will close the parth from VCC to ground through relay s coil. The coil will be energized and relay s normally open(no) will close and the bell will ring. The IJES Page 101

7 IV.CONCLUSIN AND RECOMMENDATION 4.1 Conclusion The primary goal was to design and implement a system which can be able to monitor the school timetable s time slots by controlling the school bell. the implimentation was successifull.the system will replace the current electrical bell, the same system is not only used in schools but also in some other componies where their activities depend on time slots allocation. This system will save time and money, there is no need of going to ring the bell. For distribution purpose, an installer or an executable file can be made from LabVIEW program so that it could even run on a computer without LabVIEW program installed. 4.2 Recommendation for futher work I recommend that if the work is continued, to make this system a closed syestem by putting a second controller at the receiving end side so that we can know the information about the bell. I also recommend to make a full control system for the whole school which may have an application form for student registration, a system for remotely requesting marksheet, system for library monitoring, etc REFERENCES [1] [2] [3] [4] D'Ausilio, A. (2012). "Arduino: a low-cost multipurpose lab equipment." Behav Res Methods 44(2): [5] Fernandez-Lopez, H., et al. (2012). "ZigBee-based remote patient monitoring." Stud Health Technol Inform 177: [6] [7] The IJES Page 102